Treating damaged arteries to preserve desired blood flow often comprises the placement of a thin-walled tubular device, known as a graft or stent, within the damaged artery. These device are used to treat congenital malformations or acquired abnormalities, such as aneurysms, or for the therapeutic occlusion of selected vessels.
Arterial aneurysms are formed when a section of blood vessel wall, weakened due to age, disease, congenital malformation or trauma, expands in response to the pressure of the existing blood flow to form a bulge or pocket in the arterial wall. The normal pathway of blood flow is interrupted, and the bulging aneurysmal wall is at risk for rupture. Aneurysms may occur in virtually any artery in the body, from the large ascending aorta to smaller cerebrovascular vessels such as the basilar artery.
Other arterial defects which disrupt normal blood flow include arterial dissection, wherein a partial tear of the artery wall allows blood to collect between the layers of the vessel wall and results in bulging of the vessel wall and narrowing of the normal blood flow path. Trauma may rupture blood vessels, allowing the formation of a hematoma around the damaged vessel. The hematoma may form a pseudoaneurysm, which is an aneurysm without a defined vascular wall.
Treatment of the above vascular defects includes re-defining normal blood flow by isolating the aneurysmal area from the normal circulation pathway. Methods of treatment include exposing the aneurysm surgically and ligating the aneurysm with sutures and/or metal clips; investing the aneurysmal pouch with plastic or other materials; and coagulating the contents of the aneurysmal pouch using cautery.
In some situations it may be desirable to define new blood flow pathways. In certain cases the treatment of tumorous growths includes occluding an artery supplying blood to tumor tissue. Fistulas are anomalous connections between an artery and another vessel; obstructing this connection may be required to establish desired blood flow.